Binding descriptor sets that use VK_WHOLE_SIZE with a dynamic offset
results in the VUID-vkCmdBindDescriptorSets-pDescriptorSets-01979
validation error.
Updated the updateDefaultUniformsDescriptorSet function to use the
uniform's size instead of using VK_WHOLE_SIZE.

Bug: angleproject:5924
Tests: dEQP-GLES31.functional.shaders.multisample_interpolation.*
       SimpleStateChangeTest.UniformUpdateTest*Vulkan
       UniformTestES3.MatrixUniformUpload*Vulkan
Change-Id: Ie4633af61d59a9401f599d336a5b9040cdf18004
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2950309Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>